My virtual keyboard keeps appearing while I'm reading Microsoft Office document every time I touch the screen.
This is by-design behavior. Microsoft Office apps are designed for text modifying, and Parallels Access recognizes the fields for text-editing. It makes the keyboard bring up.
For convenient text reading from Microsoft Office apps, please disable 'Show keyboard automatically' option:
Open iPad Settings
Choose Parallels Access
Disable Show keyboard automatically option.
To activate the virtual keyboard tap on the screen with three finpgers or tap on the keyboard icon on the toolbar.